Inertially operated safety switch

ABSTRACT

A gravity or inertially operated safety switch for use with electrical systems of vehicles wherein liquid mercury or other electrically conductive fluid is normally contained between two axially aligned connectors for completion of an electrical circuit and wherein upon impact or sudden deceleration of the vehicle the housing containing the mercury rotates about the connectors so that the mercury is removed from between the connectors and the electrical circuit therebetween is broken. The housing also has an electrically conductive wire embedded therein for normally completing a second circuit through two detents whereby this second circuit is opened when the housing rotates upon impact and the wire is no longer in contact with the detents.

United States Patent William O. Swanson 303 Leslie Laue, Columbia, Mo.65201 862,298

Sept. 30, 1969 Mar. 23, 1971 Continuation-impart of application Ser. No.829,911, June 3, 1969, now abandoned.

lnventor Appl. No. Filed Patented INERTIALLY OPERATED SAFETY SWITCHm13,571,s3s

Primary Examiner-Robert K. Schaefer Assistant Examiner-M. GinsburgAttorney-Cushman, Darby and Cushman ABSTRACT: A gravity or inertiallyoperated safety switch for use with electrical systems of vehicleswherein liquid mercury or other electrically conductive fluid isnormally contained between two axially aligned connectors for completionof an electrical circuit and wherein upon impact or sudden decelerationof the vehicle the housing containing the mercury rotates about theconnectors so that the mercury is removed from between the connectorsand the electrical circuit therebetween is broken. The housing also hasan electrically conductive wire embedded therein for normally completinga second circuit through two detents whereby this second circuit isopened when the housing rotates upon impact and the wire is no longer incontact with the detents.

PATENTEDHAH23I97! 3,571,538

a; INVENT OR M24 00/ 7 0. fkw/msa/v ATTORNEYS KNERTHALLY OPERATED SAFETYSWITCH This application is a continuation-in-part of application Ser.No. 829,911, filed Jun. 3, 1969 for lnertially Operated Safety Switch,and now abandoned.

The present invention relates to safety switches and more particularlyto a gravity or inertially operated mercury safety switch which may bemounted on a vehicle to disconnect the electrical system thereof in theevent of an accident to greatly reduce the potential of fire from sparksdue to electrical shorts. The present invention provides for a uniquearrangement of a weighted housing together with a mercury-receivingtrough which is located between a pair of axially aligned electricalconnectors whereby upon the sudden deceleration of the vehicle themercury is removed from between electrical connectors to open theelectrical circuit of the vehicle.

An object of the present invention is the provision of a gravity orinertially operated safety switch for use with vehicles.

Other objects and features of the invention will become apparent tothose of ordinary skill in the art as the disclosure is made in thefollowing description of a preferred embodiment of the invention asillustrated in the accompanying FIGS. in which:

H6. 1 is a side elevation view of the switch, partly in phantom,illustrating the direction of rotation of the hollow housing member ofthe switch;

FIG. 2 is a section of the device taken on the line 2-2 of FIG. 1looking in the direction of the arrows; and

FIG. 3 is a fragmentary cross-sectional view of the trough portion ofthe housing member taken on the line 3-3 of FIG. 2 looking in thedirection of the arrows.

With reference now to the drawings, wherein like reference charactersdesignate like or corresponding parts throughout the several views,there is shown in FIGS. 1-3 a base member which is adapted to be mountedin close proximity to the vehicle battery by the fastening means 12,which may be screws or the like, and which are located in the lowerportion of the base member. A pair of connectors 14 and 16 are mountedin the base member 10 in fixed positions and in axial alignment with oneanother. These connectors are adapted to be connected into theelectrical system, e.g. to the battery, of the vehicle and units havebeen built and successfully tested at currents up to 200 amps,

A hollow housing member 18 is mounted on the connectors 14 and 16 andwithin the base member 10 for rotation about the common axis oftheconnectors. The housing member includes a pair of depressed portions20 and 22 in the exterior surface of the housing member for receiving apair of adjustable elements or detents 24 and 26, respectively, whichare located within the base member in adjustable relationship therewith.A weight member 28 is fixedly attached to the end of the housing member18 which is located farthest from the connectors.

A band of electrically conductive material such as a strand of wire 29is partially embedded in or located on the outer surface of the housingmember 18 and preferably just off of the center of the depressedportions 20 and 22. This wire normally contacts the detents 24 and 26,which may be electrically conducting screws or similar fastening means,when the housing member 18 is in the upright position, and the detentscan be conventionally connected to electrical conductors 31 and 33 whichare connected into the electrical system, egg. to the alternator (notshown). The strand 29 may completely encircle the housing member or mayextend only halfway around so as to complete an electrical connectionbetween the detents 24 and 26 when the housing member is upright.

The housing member 18 also includes a mercury or other electricallyconducting fluid material receiving trough which is located between theconnectors 14 and 16 and which normally contains a small amount ofelectrically conductive fluid material 32, such as mercury, to enablethe completion of an electrical circuit between the connectors andthroughout the electrical system of the vehicle.

The base member 10 and the housing member 18 are preferably comprised ofelectrically insulating material and the connectors 14 and 16 arepreferably threaded and contain the nuts 34, 36, 38 and 40 thereon forenabling the connection of the battery cables or other electricalconductors to the connectors.

In the operation of the switch, the adjustable detents 24 and 26 are setso that they will not permit the unlatching of the housing member 18therefrom under normal braking loads, but will permit the unlatchingupon impact of the vehicle, such as might occur in an accident. Undernormal conditions of operation, the housing member 18 is oriented in avertical direction, as shown in the FlGS., so that the mercury 32 islocated at the bottom of the V-shaped trough 30 and between theconnectors 1d and 16 to enable the completion of the electrical circuitof the vehicle therethrough. Also the wire strand 2? is in electricalcontact with detents 24 and 26 to enable completion of the electricalcircuit therethrough. As an example, the connectors 14 and 16 areconnected to the battery (not shown) while the detents and the wire 29complete the circuit with the alternator of the vehicle (not shown). lnthe event of an accident, the impact causes the weighted housing member18 to become unlatched from the detents 24 and 26 so that the detents nolonger rest within the slightly depressed portions of the housing 20 and22 and no longer contact the wire 29. The force of inertia then causesthe rotation of the housing member and the weight member about theconnectors 14 and 16 so that the mercury 32 runs out of the troughbetween the connectors M and 16 and breaks the electrical circuit. As aresult, the ignition or alternator circuit will initially be opened withthe same effect as if the ignition switch of the vehicle had been turnedoff. As the rotation of the housing continues the battery circuitthrough connectors 14 and 16 and mercury 32 will also be opened.

Thus, all power from the vehicle battery to the electrical system andfrom the alternator is disconnected and the electrical system of thevehicle is completely inoperative so that the potential for fire isgreatly reduced since the hazard of sparks from electrical shorts iseliminated. The weighted housing acts as a pendulum so that oncedetented it always swings to a position in which the circuit is opened.After the housing member and the weight member have been rotated fromtheir normal position it is a simple matter to reset the switch and torestore the power when needed by simply rotating the housing member backinto its normally vertical position so that the detents 24 and 26 againengage the depressed portions 20 and 22 and the wire 29 of the housingmember 18.

It can also be seen that in addition to breaking the circuit upon theimpact of an accident the present safety switch operates by means ofgravity to open the circuit of the vehicle in the event that the vehicleflips over. When this occurs, the mercury 32 also runs out of the trough30 so that the electrical circuit between connectors 14 and 16 isbroken. Thus, the

switch of this invention is both an inertially operated and a gravityoperated safety switch.

Obviously many modifications and variations of the present invention arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

l claim:

1. A gravity or inertially operated safety switch for use withelectrical systems of vehicles, comprising:

a base member for mounting the switch on the vehicle;

fastening means affixing said base member to the vehicle in a fixedposition;

a pair of connectors mounted in said base member and positioned in axialalignment with one another;

said connectors being adapted to be connected into the electrical systemof the vehicle;

a hollow housing member mounted on said connectors and within said basemember for rotation about the common axis of said connectors andincluding a pair of depressed portions in the exterior surface of saidhousing member;

a weight member fixedly attached to the end of said housing memberlocated farthest from said connectors;

said housing member including a mercury-receiving trough therein betweensaid connectors and normally containing a small amount of electricallyconductive mercury to ena ble the completion of an electrical circuitbetween said connectors; and

a pair of adjustable elements mounted in said base member for normallycontacting respective ones of said depressed portions in said housingmember whereby said housing member is normally maintained in an uprightposition with the mercury located in said receiving trough and wherebysaid elements unlatch from said depressed portions to enable therotation of said housing member about said common axis of saidconnectors and to enable the movement of said mercury out of said troughto break the electrical circuit between said connectors when the vehicleis abruptly decelerated as upon the occurrence of an impact in anaccident.

2. A safety switch as in claim 1 wherein said base member is comprisedof electrically insulating material.

3. A safety switch as in claim 2 wherein said housing member iscomprised of electrically insulating material.

4. A safety switch as in claim 1 wherein said adjustable elements arepositioned in axial alignment with one another.

5. A safety switch as in claim 4 wherein said adjustable elements aredetents which are adjustable so as not to unlatch under normal brakingconditions.

6. A safety switch as in claim 1 wherein said receiving trough is agenerally V-shaped trough.

7. A safety switch as in claim 1 wherein said adjustable elements areadapted to be connected into the electrical system of the vehicleincluding electrically conducting means affixed to said housing memberand in normally electrically conducting relationship with saidadjustable elements.

8. A safety switch as in claim 7 wherein said electrically conductingmeans includes a strand of wire at least partially encircling saidhousing member.

9. A safety switch as in claim 8 wherein said wire is partially embeddedin the outer surface of said housing member and wherein said wire islocated within said depressed portions.

10. A gravity or inertially operated safety switch for vehicles,comprising:

means for mounting the switch on the vehicle;

connector means mounted in said mounting means;

housing means rotatably mounted with respect to said connector means;said housing means having an electrically conductive fluid receivingportion therein for normally containing an amount of electricallyconductive fluid between said connector means and in electrical contacttherewith; and

means operatively associated with said housing means and with saidmounting means for normally maintaining said housing means in an uprightposition and including an inertial element whereby said maintainingmeans enable the rotation of said housing means upon the occurrence ofan impact as in an accident to permit the movement of said fluid frombetween said connector means to break the circuit of the vehicle.

1. A gravity or inertially operated safety switch for use withelectrical systems of vehicles, comprising: a base member for mountingthe switch on the vehicle; fastening means affixing said base member tothe vehicle in a fixed position; a pair of connectors mounted in saidbase member and positioned in axial alignment with one another; saidconnectors being adapted to be connected into the electrical system ofthe vehicle; a hollow housing member mounted on said connectors andwithin said base member for rotation about the common axis of saidconnectors and including a pair of depressed portions in the exteriorsurface of said housing member; a weight member fixedly attached to theend of said housing member located farthest from said connectors; saidhousing member including a mercury-receiving trough therein between saidconnectors and normally containing a small amount of electricallyconductive mercury to enable the completion of an electrical circuitbetween said connectors; and a pair of adjustable elements mounted insaid base member for normally contacting respective ones of saiddepressed portions in said housing member whereby said housing member isnormally maintained in an upright position with the mercury located insaid receiving trough and whereby said elements unlatch from saiddepressed portions to enable the rotation of said housing member aboutsaid common axis of said connectors and to enable the movement of saidmercury out of said trough to break the electrical circuit between saidconnectors when the vehicle is abruptly decelerated as upon theoccurrence of an impact in an accident.
 2. A safety switch as in claim 1wherein said base member is comprised of electrically insulatingmaterial.
 3. A safety switch as in claim 2 wherein said housing memberis comprised of electrically insulating material.
 4. A safety switch asin claim 1 wherein said adjustable elements are positioned in axialalignment with one another.
 5. A safety switch as in claim 4 whereinsaid adjustable elements are detents which are adjustable so as not tounlatch under normal braking conditions.
 6. A safety switch as in claim1 wherein said receiving trough is a generally V-shaped trough.
 7. Asafety switch as in claim 1 wherein said adjustable elements are adaptedto be connected into the electrical system of the vehicle includingelectrically conducting means affixed to said housing member and innormally electrically conducting relationship with said adjustableelements.
 8. A safety switch as in claim 7 wherein said electricallyconducting means includes a strand of wire at least partially encirclingsaid housing member.
 9. A safety switch as in claim 8 wherein said wireis partially embedded in the outer surface of said housing member andwherein said wire is located within said depressed portions.
 10. Agravity or inertially operated safety switch for vehicles, comprising:means for mounting the switch on the vehicle; connector means mounted insaid mounting means; housing means rotatably mounted with respect tosaid connector means; said housing means having an electricallyconductive fluid receiving portion therein for normally containing anamount of electrically conductive fluid between said connector means andin electrical contact therewith; and means operatively associated withsaid housing means and with said mounting means for normally maintainingsaid housing means in an upright position and including an inertialelement whereby said maintaining means enable the rotation of saidhousing means upon the occurrence of an impact as in an accident topermit the movement of said fluid from between said connector means tobreak the circuit of the vehicle.